(CNN) -- A Florida man charged with murder in the fatal shooting of a teenager amid an argument over loud music at a gas station pleaded not guilty Monday.

Michael Dunn, 45, entered his plea during a hearing Monday morning at the Duval County, Florida, jail.

Dunn told investigators he fired at a car in which Jordan Davis, 17, and three of his friends were sitting because he felt threatened by them. No guns were found inside the teens' car, the Jacksonville Sheriff's Office said.

The case against Dunn, who has been jailed without bond since the November 26 shooting at the Jacksonville, Florida, gas station, has been compared to the "stand your ground" case in which George Zimmerman is charged with killing Trayvon Martin

Similar to Martin, Davis was an African-American teen.

Dunn, indicted on a first-degree murder charge last Thursday, is no "vigilante" but did feel threatened and shot out of "self-defense," his lawyer said two days after his arrest

"There are no comparisons to the Trayvon Martin situation," said Robin Lemonidis, Dunn's attorney. "He is devastated and horrified by the death of the teen."

Dunn told authorities that he had asked the teens to turn down the blaring music coming from their vehicle, which was parked next to his as he waited for his girlfriend to return to the carHe heard threats from the teens, Dunn told police, and he felt threatened and thought he saw a gun in their car. He grabbed his gun and fired at least eight shots, authorities said.

"It's about loud music and it's also about anger, about having a concealed weapon in your car, knowing you have it and feel bold enough to use it because you're being shielded in the state of Florida," Jordan Davis' father, Ron Davis, told CNN. "They tell you if you have a concealed weapon, these are some of the things you can do. If you feel you're threatened in any way, then you are allowed to use your weapon."